Rupture disk assembly



Sept 2, 1952 H. R. sPENcE, JR- 2,608,719

RUPTURE DISK ASSEMBLY Filed Dec. 27, 1948 IN V EN TOR.

HAM v kaas/fr P5/VCE, JR.

Patented Sept. 2, 1952 RUPTURE msx ASSEMBLY Hai-ry Robert Spence, Jr.,Nitro, W. Va., as signorj l to AmericamViscose Corporation, Wlmingtom KDel.,v a corporation of Delaware j Application December 27, 1948serialN9. ansia i The present invention relates to the production of filamentssuch as those obtained by forcing a lament-forming liquid throughT smalldiameter orifices. Y i Y l .l

In producing viscose rayon lamentaifor examfple, a spinning solution ofcellulose xanthate is forced through orifices ranging injdiameter'from0.001 to 0.003 of an inch.v .Thetotalgnumberjof such orifices may rangefrom 40 orv 50't`o`s'everal thousand in a single spinneret. In service',these orifices may become Wholly or vpartially clogged because ofimpurities, or imperfectly homogenized viscose spinning solution, orcoagula which occasionally prematurely form in a spinning `soluf tion,or structural imperfections of the spinneret. When this conditionoccurs, excessive hydraulic forces are imposed upon the spinneret 4whichmay cause distortion or rupture thereof. As` costly corrosion-proofmaterials and` much labor is required for constructing satisfactoryspinnerets, it is desired to keep the maintenance `and the replacementcost al; a minimum.v Moreover, as the orifices become plugged, thediameter of the extruded filament is changed. Undertheconditions when,for example, theorifiesA become reduced in diameter by the deposition)ofr material on their inner walls, the diameterrjoi" Athe fllaments isreduced. Another condition thatmay occur, is when some of the holesbecome plugged butothers remain' open and the filaments are extrudedfrom the open holes under increased pressure. As the speed of thegodetwhich withdraws the lament from the spinneret remains unchanged,these filaments are therefore larger in diameter since the volume ofsolution extruded per orifice is greater at increased pressure. As thegodet imposes a certain desired stretch Vupon the filament whichproduces substantial `elongation and reduction in denier as wellas'orienting of the filament cells in the filament immediately afterleaving the spinneret, ai substantial ,change in diameter of thefilaments' occurring as al result of the change in the condition ofthespinnret, varies the degree of stretchingu imposed on the yarn andresults in a rayon material ofnon-uniform and undesired characteristics.

The principal objectsY of the invention,A therefore, are: to provide apressure-responsive device in an extrusion apparatus forfllaments,.lmsor other articles which isfsensitive to rises in pressure resultingfrom plugged filters, spinnerets or other types of orifice plates;toadaptusuch 'a device to present extrusion machinery; and to producefilaments of uniform denier andelongation. Other objects, features andadvantages of the inventionrwill Ileccov y description `ofA the 1inventiom and, the. drawings.

In the drawing illustrative 'of the'invention,

. Fie'. llis a. fraementarrew. partly insetien as seenA fromthesideof-the filament extruding Jamming-showing an tion;

f the' apparatus, .Sernin Fig. z isan'fe dm Fig-1; N ,A

Fig. 3 is an enlargeds tiona vlevv of a portion cf-the'apparatus seen inFifg.-`1; and j, A Fig. 4 is a diametric'al section of a rupture plateaccording tothe invention.'

Briefly, the invention Yconflprises providing a pressure4rupturablefelementjini a-Wall of any means for conducting affilainentformingv solution from a `feed device'to an oriilce plate. The inventionmay be used o n-many types of'lament extrusion equipment, butjsin hemanufacturing of rayon filaments constitutesjanimportant field ofapplication,` itwill be described with respect to the making Vofviscose. rayon yarn.

A ReferringspeoificaliytoFig l, a portion of the rayon `spinning'machinelsI shown, vwherein the spinning solution jiscd l uctegdfrom apump (not shown) through L-'CQndul .8 and through a swivel connectionintfoythe lte a .I Iiz ',Thejflterbase I I is pivotable onanaxisexter'lding from ones'ide through a threaded "screWydevice v9fwhch [is adjustable Within a; threaded 'aperture' extending through thebracket I3.. fLDevice 9. terminates in a round lug In'which f'ltsvvithina shallow complementary recess I6 pro-vided'for it on the side ofthe'fllter base II. The'oth'er side of the filter base II is providedAwith 'ai' tapered. recess I4 coaxial with the pivoting aXSof thebase,adapted for receiving arounded andtubularinsert I5. Bracket I2 isprovidedpwith a 'fluid-conducting passageway Il and recessesat 'each endof the passageway for receiving the insert I5 and the threaded fittingI8 `which connects the tube 8 to the bracket I2. By adjusting the screwdevice 9, the surface withinrecess I4 is forced tightly against the endof `thein'sert. I5 which in turn is forcedtightly againstthe surfacesWithin the recess at I9. A passageway extends inwardly of thefilterbasejIIQ-from fthe recess' I4 to a threaded aperture shown `inFigl 2. Solution, passing through the lterfbase II flows into the filtercase 20 andthroughfa. conventional filter element contained [thereimfand also through a curved glass tube 2l into'xth'e spinneret supportedwithin the coupling 2'3 submerged Within a vspin bathbelow the indicatedliquid level 24. S I- Fig. 3 is an enlarged sectional view of the filtermetti/icas lathe following Y 3 base Il shown in Fig. 1. The body of thefilter base is of a type which has been Widely used in conventionalrayon spinning machinery. The lter base I l is a desirable portion ofthe spinning machinery to which to adapt the present invention,especially since the iilter base is normally provided with a threadedaperture or recess 21. The rupture closure or disc 25 and an outerprotective closure or cap 30 are held in place valong an annular recess29 within the aperture 21 by an exteriorly threaded annulus 28, thelower surface of which bears on an annular flange 3i of cap 3D. Flange3|, in turn, bears onV an annularv flange 33 of the disc 25. Flange 33isforced against a gasket 32 of resilient material suchlas:

vulcanized rubber composition for positive sealing of the aperture 21.The cap 3U is made oi any suitable material such as metal stampings orIt may be made, if I moldable plastic material. desired, of atransparent plastic material such Vas a vinyl chloride-vinyl acetatecopolymer, so

that the disc may be Visually inspected at any time. The cap 30 has anend wall, spaced from the disc 25 to provideachamber therebetween, and alateral wall extending lfrom the end wall tothe flange 3|-. The cap 3Bis apertured preferably in the lateral wall thereof, e.. g. by theaperture 34. The arurture 34 Vprovides, free communication between theoutside space 'or' atmosphere and the chamber within the cap 35 betweenits end wall and the disc 25 to permit the escape of solution, anddeection thereof into space not occupied by personnel, vupon rupturing`of the disc 25. I

Disc 25 is preferably of concave-convex plate construction. Such adischas vbetter structural strength and may be thinner gauge than a flatdisc for opposing the hydraulic forces .to vwhich it is subjected. Thisconstruction of the disc and the fact that the inlet and outlet ducts 35and 35 respectively have ports at opposite ends of the space or chamber31 between the bottom of the recess 21 and the inner'wall of the Vdisc25 causes the liquid passing through the inlet, port of chamber 31 atthe terminus of duct35 to approach the inner surface of the disc at anangle and sweep along said surfaceuntil itfreache's` the outlet port ofchamber 31 associated with duct 35. In this manner the chamber 31 ismaintained free of over-aged, partiallyset spinning solution Yand theinner surface of disc 25 is swept free o'any materials having a tendencyto adhere to the disc. The disc 25 may be constructed of anysubstantially rigid lcorrosion-resistant material having the requiredtensile strength. Inl the practice of the invention, a. nickel-platedaluminum disc is found very satisfactory for use as a rupture disc onequipment for ,handlingv viscose solutions. For cellulose acetatesolutions, stainless steel discs are satisfactory. V The thickness ofthe disc will be dependent upon the maximum operating pressure to whichit ispermissible to subject the spinneret while allowing a margin ofsafety, and will be of the order of a few thousandths of an inch. Thedisc may be of such thickness that it of the filter element contained inthe lter case 20. Consequently in the apparatus shown, plugging ofeither the spinneret or the filter may result in bursting of the disc25. However, such a rupturable element as the disc 25 may be installedin a suitable aperture therefor in the wall of any portion of theapparatus through which spinning solution may flow between a pumpingmeans and the spinneret supported in the spinneret coupling 23.

Obviously, many changes and variations may be made in the details of theinvention as specifically set forth without departing from the natureand spirit of the invention as defined in the appended claims.

I claim: i

1. An extrusion machine for producing articial films, filaments, andother articles from a liquid-to-plastic material comprising positivedelivery means for the material, an oriced extrusion plate, duct meansfor carrying the material from the delivery means to the extrusionplate, an intermediate section of the duct means comprising a chamberhaving an inlet port and an outlet port spaced adjacent opposite ends ofthe chamber for connecting it in series with adjacent sectionsjof the,duct means, and a substantially rigid closure constituting a wall ofsaid chamber and extending over the ports, said closure havingsuiic'ientstrength to resist rupture up to but not above a predeterminedpressure of the material and the extrusion plate having a strengthsubcient to resist rupture exceeding said pressure, a

protective cap secured in position over the will rupture at anypredetermined increasev in closure andY having a Wall thereof spacedfrom the closure to provide a chamber therebetween, and an aperture inthe cap providing free communication between the outside atmosphere andthe last-mentioned chamber.

2. A machine for spinning artificial filaments comprising pumping means,a spinneret, a base, a lter, a case for housing the lter secured to thebase, said base and case being connected between the pumping means andthe spinneret and in series therewith, a recess in the base in seriescommunication with the pumping means and the spinneret, a substantiallyrigid closure secured in the recess and being made of a strength suchthat it will rupture at a predetermined pressure which is less than thatwhich the spinneret is adapted to withstand, a cap for the closurehaving an end Wall and a lateral wall, said end wall being spaced fromthe closure toprovide a chamber therebetween, and an aperture inthelateral wall of the cap providing free communication between the outsideatmosphere and the chamber.

3. A spinning machine as defined in claim 2 whereink the spaced cap istransparent.

, 4. A machine for spinning artificial filaments comprising an assemblypivotable with respect to a liquid spinning solution supply means, saidassembly comprising a pivotable base, a filter case attached to thebase, a spinneret, conduit means for leading the spinning solution fromthe iilter case to the spinneret, a recess in the base, a substantiallyrigid inner closure secured in the recess and providing an enclosedspace between the bottom of the'recess and the closure, an inlet ductextending through the base to one end of the space, an outlet ductextending from an opposite end of the space through the base to thefilter case, said closure being rupturable at lower pressure than thespinneret, an outer closure secured in the recess and having an outerwall portion spaced from the inner closure to REFERENCES CITED provldea' chamber therebetween and an aper' The following references are ofrecord in the ture in the outer closure providing free communifue of thit nt. cation between the outside atmosphere and the TSJDTD'STATESPATENTS last-mentioned chamber. 5 v v 5. A machine as defined in claim 4in which Number Name Date the inner closure is of concavo-convex shapewith 733,213 Joy July 7, 1903 the concavity facing. the bottom of therecess. 1,446,585 Riotte Feb. 27, 1923 6. A machine as defined in claim4 in which 1,959,822 Greve May 22, 1934 the outer closure has an endWall and a lateral 10 wall and the aperture is provided in a lateralwall FOREIGN PATENTS of the outer closure. Number Country Date HARRYROBERT SPENCE, JR. 395,333 Great Britain Oct. 9, 1931

